MATH319 Slides

98 Partial fractions and Laplace transforms

f⁢(s)=q⁢(s)+r⁢(s)h⁢(s)

where r⁢(s)/h⁢(s) is strictly proper. Now by the fundamental theorem of algebra,

h⁢(s)=b⁢∏j=1n(s-λj)mj

where the λj∈𝐂 are distinct. Then by the usual partial fractions calculation, we look for coefficients ak such that

r⁢(s)h⁢(s)=∑kak,nk(s-λk)nk,

with integers 1≤nk≤mk. The poles and coefficients are unique.